this ppt is prepared by my respectable mam israt jahan Bulbul, assistant professor, department of pharmacy, southeast university.

1. Israt Jahan Bulbul
Assistant Professor
Department of Pharmacy
SEU, Banani, Dhaka

2.  Definition:
 Glycosides are non-reducing organic
compounds that on hydrolysis with acids,
alkalis or enzymes yield:
A sugar part (or glycone, formed of one or more
sugar units).
A non-sugar part (or aglycone, also called genin).

3. Solubility:
 Glycosides are water soluble compounds and
insoluble in the organic solvents.
 Glycone part: water soluble, insoluble in the
organic solvents.
 Aglycone part: water insoluble, soluble in
the organic solvents.
 Some glycosides are soluble in alcohol.

4.  Colorless solid, amorphous, nonvolatile (flavonoid-
yellow, anthraquinone-red or orange.
 Give positive reaction with Molisch's and Fehling's
solution test (after hydrolysis).
 They are water soluble compounds, insoluble in
organic solvents. when a glycosides has a lot of
sugars its solubility in water decrease.
 Most of them have bitter taste (except: populin,
glycyrrhizin).
 Odorless except saponin (glycyrrhizin).
 Glycosides hydrolyzed by using mineral acids and
temperature or by using enzymes such as:
 a- Emolsin (Bitter almond seeds).
 b- Myrosin or Myrosinase (black mustard seeds).

5.  Step I: Transfer of an uridylyl group from uridine
triphosphate to a sugar, 1-phosphate. Enzymes
catalyzing this reaction are reffered to as uridylyl
transferases.
UTP (Uridine Triphoshate) +sugar-1-phoshate =
UDP-sugar + ppi(Pyrophosphate inorganic).
 Step II: The subsequent reaction involves the
transfer of the sugar from uridine diphosphate to a
suitable acceptor (aglycon); here the responsible
enzymes are glycosyl transferases.
UDP-sugar +acceptor (aglycone)= Acceptor-sugar
+UDP

6.  Converting toxic materials to non or less toxic.
 Transfer water insoluble substances by using
monosaccharide.
 Source of energy (sugar reservoir).
 Regulation for certain functions(growth).
 Some have beautiful colours(pollenation
process).
 Some glycosides have antibacterial activity, so
they protect the plants from bacteria and
diseases.

7. According to their therapeutic effects
CHF and cardiac muscles stimulators such as:
a-Digitalis glycosides: digoxin, digitoxin,
gitoxin (Fox glove leaves).
b- Ouabain: Strophanthus gratus seeds.
c- K-strophanthin -Strophanthus kombe seeds.
d- Scillaren A,B which isolated from red and white
Squill bulbs.

8.  Laxative group of glycosides:
 a- Sennoside A,B,C,D (Senna leaves and fruits).
 b- Cascaroside A,B (Cascara bark).
 c- Frangulin and glucofrangulin(Frangula bark).
 d- Aloin and barbaloin (Aloe vera and Aloe barbadensis juice).
 Local irritant group:
a-Sinigrin(Black mustered seeds_Brassica nigra)
b-Sinalbin(White mustered seeds_Brasica alba)
 Analgesics and antipyretics:
Salicin (Salisylic acid - Willow or Salix bark)
 Keeping elasticity of blood vessels like:
Rutin_Rutoside (Bitter orange peels, Lemon peels)
 Anti-inflammatory group:
a- Aloin for 1)acne 2)peptic ulcer
b-Glycyrrhizin

9. According to glycone part
 Glucose _ glucoside group like in
Sennoside.
 Rhamnose _ Rhamnoside like in frangullin.
 Digitoxose _ Digitoxoside like in digoxin.
 Glucose and Rhammnose _
Glucorhamnoside _ glucofrangulin.
 Rhamnose and glucose _ Rhamnoglucoside
_ Rutin.

10. Classification of glycosides on the basis of the linkage
between glycone and aglycone part
 O-glycosides : in these glycosides the sugar part is linked
with alcoholic or phenolic hydroxyl or carboxyl group.
 S-glycosides : in these glycosides the sugar attached to a
Sulfur atom of aglycone such as in sinigrin.
 N-glycosides : in these glycosides the sugar linked with
Nitrogen atom of (-NH2,-NH-)amino group of aglycone
like in nucleosides DNA,RNA
 C-glycosides : in these glycosides the sugar linked
(condensed) directly to Carbon atom of aglycone like in
aloin.

11. Classification of glycosides according to
aglycone part :
1. Alcohol glycosides: if aglycone part is alcohol
-this group called alcoholic group like Salicin,
populin
2. Aldehyde glycosides: if aglycone part is
aldehyde- this group called aldehydic gr. like
glucovanillin.
3. Phenol glycosides: if aglycon part is phenol this
group called phenolic group like arbutin .
4. Cyanogenetic or cyanophoric glycosides:
Cyanogen is the aglyconeand they yield
hydrocyanic acid on hydrolysis.e. g. amygdalin.

12. 5. Isothiocyanate glycosides: isothiocyanate glycosides
contain a part which is constituted with
allylisothiocyanate (-S=C=N-) like sinigrin or
sinalbin.
6. Anthraquinone glycosides: In these glycosides sugar
moeity is attached to an anthracene aglycone e.g.
Sennoside, emodin.
7. Steroidal glycosides (cardiac): These contain a
sterol as an aglycone e.g. Digoxin
8. Flavonoid glycosides: A flavone ,flavonol, flavanone
aglycone is present in these glycosides. E.g. Rutin,
Hesperidin.
9. Triterpenoid glycosides or saponin glycosides: A
triterpene molecule is condensed with a sugar
component. E. g. glycyrrhizin .

13.  Cardiac glycosides are a group of natural products
characterized by their specific effect on myocardial
contraction and atrioventricular conduction.
 In large doses they are toxic and bring about cardiac
arrest in systole, but in lower doses they are important
drugs in the treatment of congestive heart failure.
 They have a diuretic activity. Since, the improved
circulation tends to improve renal secretion, which
relieves the edema often associated with heart failure.

14.  Scrophulariaceae
 Digitalis purpurea leaves (foxglove)
 Digitalis lanata leaves – white flowers
 Apocyanaceae
 Strophanthus vine seeds – Africa
 Liliceae
 Urginea bulbs (squill) – Europe, India
 In toads
 Cardiac glycosides are also found in animals
only in exceptional cases.

15.  The structure comprise a steroidal aglycone of the
(C23) cardenolide type or of the (C24) bufadienolide
type, and a sugar moiety, most often an
oligosaccharide.
 All of the aglycones have in common the classic,
tetracyclic, steroidal nucleus.
 The A, B, C and D rings normally have a cis-trans-cis
configuration or less often, a trans-trans-cis
configuration.
 Also common to all the aglycones is the presence of
two hydroxyl groups: one is a 3β secondary alcohol,
the other is a 14β tertiary alcohol.
 All of the aglycones have a β constituent at C-17: an
α,β-unsaturated lactone.

16.  The size of the lactone ring (R) distinguishes two
groups of aglycones: the C23 cardenolides with an α,β-
unsaturated γ-lactone (= butenolide) and the C24
bufadienolides with a di-unsaturated δ-lactone (=
pentadienolide).
 The sugar moiety is generally linked to the aglycone
through the hydroxyl group at C-3.The sugars can
modify the activity (potency, toxicity), the solubility,
the diffusion through membranes, the rate of
absorption and transportation of the glycosides.

17.  The cardiac activity is linked to the aglycone.
 The sugar moiety does not participate directly in the
activity, but its presence enhances the activity and
modulates it by modifying the polarity of the
compound.
 The presence of a certain number of structural
elements is required for, or at least favorable, to the
activity:
1. The lactone at C-17, and it must be in the β configuration.
2. The configuration of the rings. The activity is maximized
when the A, B, C and D rings are in the cis, trans, cis
configuration. The C and D rings must be cis fused.
3. The substituents. The inversion of the configuration at C-3
diminishes the activity, but 3-deoxy compounds are not
completely inactive.

18.  Cardiac glycosides increase the force and speed
of contraction of the heart. The glycosides are
thought to act at the membrane level, by
inhibition of the Na-K ATPase, which would
result in an increase of the intracellular calcium
ion concentration.
 Therapeutic indications:
 Cardiac glycosides are currently indicated for:
1. Cardiac insufficiency with low output (generally
in combination with diuretics), particularly when
there is atrial fibrillation.
2. Supraventricular rhythm abnormalities: to slow
down or decrease atrial fibrillation or flutter.

19. Several species of Digitalis yield
pharmacologically active principles. The most
important of these species are Digitalis
purpurea and Digitalis lanata.
1. Digitalis purpurea folium (Red foxglove
leaves)
0.15% − 0.4% total cardenolides, ∼ 30
glycosides Purpurea glycosides A and B
(∼60%), digitoxin (∼12%), gitoxin (∼10%) and
gitaloxin (∼10%).
2. Digitalis lanata folium (White foxglove
leaves)
0.5% − 1.5% total cardenolides, ∼ 60
glycosides Lanatosides A and C (∼50%),
lanatosides B, D, E as well as digoxin and
digitoxin.

20.  Characters:
1. The leaves are linear or oblong-lanceolate, with obtuse or
rounded apex, size 10 cm long and 4-8 cm wide. The margin is
crenate to dentate with water pores on many teeth.
2. Upper surface is pubescent, dark green, little wrinkled and
veins are depressed. The lower surface is grayish green and
veins are more prominent. Both the surfaces are hairy but the
lower surface is more hairy. Venation is pinnate.
3. Odor is distinct and taste is bitter.

21. Chemical constituents:
 Digitalis contains about 35 glycosides. The most
important chemical constituents of medicinal importance
are digitoxin, gitoxin and gitaloxin, purpurea glycosides
A and B, digoxin. It also contains digitalin , gitalin,
digitonin, tannic acid, volatile oil etc.

22.  Cardiac glycosides are currently indicated
for:
1. Cardiac insufficiency with low output
(generally in combination with diuretics),
particularly when there is atrial fibrillation.
2. Supraventricular rhythm abnormalities: to
slow down or decrease atrial fibrillation or
flutter.

23.  Strophanthus is the dried ripe seeds of Strophanthus kombe
or S. hispidus from the family Apocynaceae which contain
the principle glycosides named as
1. K-strophanthoside
2. K-strophanthin-β
3. Cymarin
 Characters:
1. The seeds are about 12 to 17 mm in length, 3 to 5mm
broad, plano-convex and lanceolate in shape with
acuminate ends silvery-grey to yellowish-green in color.
2. Endosperm is narrow, oily and white in color. The embryo
extends throughout the whole length of the seed and
consists of two leaf like cotyledons.
3. Odor is characteristic musty and taste very bitter. Reserve
food is fixed.
4. Strophanthus is a climber and the extract of the seeds of
this plant is used by the tribals as arrow poison.

24. The cardioactive constituents of
the drug in a pure crystalline
form are used for the preparation
of injections. Cardioactive
glycosides of the drug
administered in intravenous
injections act within a few
minutes, and their effect lasts for
approx. 36 hours. Their
pharmacological activity is
similar to that of Digitalis
glycosides, but Strophanthus
glycosides do not accumulate,
therefore these cardenolides are
used in the case of acute cardiac
insufficiency as life-saving
medicines.

25.  The drug contains a mixture of glycosides called K-strophanthin,
which constitutes K-strophanthoside (strophoside), K-
strophanthoside B cymarin and cymarol. Except cymarol, all other
glycosides yield strophanthidin on hydrolysis. K-strophanthoside is
the primary glycoside and on hydrolysis it gives aglycone
strophanthidin and 3 sugars cymarose, α and β glucose.

26. The drug consists of the dried
sliced bulbs of Urginea maritima
(Liliaceae) from which the
membranous outer scales have
been removed.
The characteristic constituents of
the drug are bufadienolides. In
white squill there is a mixture of
15 bufadienolides: the aglycone
is scillarenin and the principal
glycosides are scillaren A,
glucoscillaren A and proscillaridin
A. In red squill the principal
glucosides are scillirozide and
glucoscillirozide, their aglycone
part is scillirosidine.

27. Uses: In pharmaceutical industry white squill is used principally. Scillaren A
and proscillaridin A can be absorbed from the gastrointestinal tract (almost in
25%), therefore these compounds are administered orally. The therapeutic
indications include aorta-insufficiency, angina pectoris, oedema associated
with nephritis. In small doses the drug can be used as an expectorant, but in
large doses it causes vomiting.

28.  Substances of the anthraquinone type may occur both in
free state and as glycosides. Natural compounds also
contain reduced derivatives of the anthraquinones
(oxanthrones, anthranols and anthrones) and compounds
formed by the union of two anthrone molecules.

29.  Anthraquinone glycosides are often easily hydrolysed. The
following aglycones have long been established: chrysophanol
(from rhubarb and cascara), aloe-emodin (from rhubarb and
senna), rhein (from rhubarb and senna), emodin (from frangula
and cascara) and physcion (from frangula and cascara).

30.  Cascara consists of the dried bark of Rhamnus
purshianus (Frangula purshiana). It contains
not less than 8.0% of hydroxyanthracene
glycosides of which not less than 60% consists
of cascaroside A.
 Characters:
 The bark occurs in single quills or channeled or
flat pieces, 5 to 20 cm in length, up to 2 cm in
width and 1 to 4 mm in thickness, almost smooth
cork with pale brown , transversely elongated
lenticels, occasional patches of silvery grey
lichens.
 Inner surface has longitudinal striation and
transverse corrugation.
 Fracture is short and granular to the outer side but
somewhat fibrous to the inner side.

31.  (i) 4 primary glycosides
O- and C- linkages
 (ii) C-glycosides - two aloins
barbaloin – derived from aloe-emodin
chrysaloin – derived from chrysophanol
 (iii) a number of O-glycosides
derived from emodin oxanthrone, aloe-emodin,
chrysophanol
 (iv) various dianthrones
incl. emodin, aloe-emodin, chrysophanol,
herterodianthrones palmidin A B C
 (v) aloe-emodin, chrysophanol, emodin in free state
 Uses:Therapeutic indications include the short term
treatment of occasional constipation.

33.  Rhubarb consists of the whole or cut, dried
underground parts of Rheum palmatum L. or of
Rheum officinale or of hybrids of these two species or
of a mixture. The underground parts are often
divided; the stem and most of the bark with the
rootlets are removed. It contains not less than 2.2% of
hydroxyanthracene derivatives, expressed as rhein.
Rhubarb has a characteristic, aromatic odour.

34.  Characteristics:
 The Rhizome is sub-cylindrical, barrel-
shaped, conical or plano convex in shape, 3
to 12 cm in length and 3 to 8 cm in
diameter.
 The drug often occurs in pieces, described
as ‘flats’ of ‘rounds’. The surface is
smooth.
 The transversely cut surface exhibits a
numerous ‘star spots’( due to the presence
of vascular bundle) and prominent
cambium line the periphery.
 It is generally orange brown in colour and
has an uneven granular fracture.
 The drug has a characteristic aromatic odor
and a bitter, slightly astringent and gritty
taste.

35.  Chemical constituents:
The main active constituents of the drug are hydroxyanthracene
derivatives (3-12%) consisting mainly (60-80%) of mono- and
diglucosides of rhein, chrysophanol, aloe-emodin, physcion and
emodin, and only small amounts of the respective aglycones.
Dianthrone glycosides (sennosides) are also present

36.  Botanical source:
 Aloe is dried juice of the leaves of Aloe
barbadensis, Aloe ferox, Aloe perryi, Aloe vera
from the family: Liliaceae. It contains about 28%
of hydroxyanthracene derivatives calculated as
anhydrous barbaloin. The juice is obtained from
the transversely cut leaves which is concentrated
by boiling and solidifies on cooling.
 Part used: Dried juice of leaves.
 Commercial varieties of Aloe:
 Cape aloe (obtained from Aloe ferox)
 Curacao aloe (obtained from Aloe barbadensis & Aloe
vera)
 Socotrine aloe (obtained from Aloe perryi)

37.  Chemical Constituents:
 Aloe contains a mixture of crystalline glycosides known
as aloin (4-5% in cape aloe; 18-25% in curacao aloe),
aloe emodin, emodin, resin (16-63%) and volatile oil.
The principal constituents of aloin are barbaloin,
isobarbaloin, beta-barbaloin, aloe-emodin and resin.
 Uses:
 It is used as purgative and given in constipation.
 It is one of the ingredients of compound of Benzoin tincture,
an ointment of aloe gel is used to cure burns caused by heat,
sun or radiation and skin irritations.
 The plant is valued to cure many skin diseases, ulcerative skin
conditions, wounds, burns, snake bite, as hair tonic,
to treat enlarged spleen, tonic for stomach and brain.

38.  Senna occurs as dried pods, leaves of Cassia angustifolia
Known as Tinnevelly (India) and Cassia acutifolia known as
Alexandrian (Egypt) senna from the family Leguminosae. It
contains about 2.5% of hydroxyl anthracene glycosides,
calculated as sennoside B.
 Characteristics:
 Senna occurs in leaflets. The leaflets are 2-4 cm long and 1 cm wide.
 The margin is entire. Apex accuminate, lanceolate to ovate-
lanceolate, surface pubescent, venetion is pinnate, color is greyish-
green, and odor is faint, taste mucilaginous and slightly bitter.
 Epidermal trichomes are present on the leaflets which are unicellular,
conical and thick walled.

39. (i) 1 glucosides and 1,8 diglucosides
aglycones: rhein, aloe emodin
(ii) dimeric dianthrones
reduced products

40.  Properties:
 They form colloidal solutions with water that foam upon
shaking.
 They destroy red blood corpuscles by hemolysis.
 They are toxic to cold blooded animals.
 On hydrolysis they yield an aglycone called a sapogenin.
 They form crystalline compounds upon acetylation.
 It is 50 times as sweet as sugar.
 It promotes potassium depletion in blood.
 They have high molecular weight.
 Most of the Saponins are highly toxic.
 They have possessed a bitter acrid taste.

41.  According to the structure of the aglycone or sapogenin,
two kinds of saponin are recognized:
 The steroidal type (commonly tetracyclic triterpenoids,
C-27).
 The triterpenoid type (pentacyclic triterpenoids, C-30).
 Both of these have a glycosidal linkage at C-3 and have a
common biosynthetic origin via mevalonic acid and
isoprene units.

42.  Steroidal saponins
 The steroidal saponins are less widely distributed in
nature than the pentacyclic triterpenoid type.
 Steroidal saponins are of great pharmaceutical
importance because of their relationship to
compounds such as the sex hormones, cortisone,
diuretic steroids, vitamin D and the cardiac glycosides.
 Examples: Diosgenin (Dioscorea sylvatica),
Sarsapogenin (Smilax sp.).
 Pentacyclic triterpenoid saponins
 Triterpenoid saponins may be classified into three
groups represented by α-amyrin, β-amyrin and lupeol.
 Examples: Primulagenin (Primula sp.), Quillaiac acid
(Quillaia saponaria) and Glycyrrhetinic acid
(Glycyrrhiza sp.).

43.  Synonyms: Licorice, liquorice, glycyrrhiza
 Botanical source: Glycyrrhiza consists of the
dried roots and rhizome of Glycyrrhiza glabra
or G. gladulifera varities. It contains not less
than 4% of glycyrrhizinic acid.
 Family: Leguminosae

44.  Characters:
 The drug occurs in peeled or unpeeled stolons and roots, length 5-
30cm, diameter 1-2cm, cylindrical, branched or unbranched.
 The unpeeled drug is longitudinally wrinkled with occasional buds
and the peeled drug is coarsely fibrous on the surface.
 The colour varies from yellowish-brown to dark brown (unpeeled)
and yellow (peeled).
 The fracture is fibrous.
 It has faintly characteristic odor and sweet taste.
 Chemical Constituents:
 Glycyrrhiza contains 6-14% of glycyrrhizin which is 50 times as sweet
as sugar. Upon hydrolysis the glycoside loses its sweet taste and is
converted to the aglycone glyrrhetic acid plus 2 molecules of
glucuronic acid. Glycyrrhetic acid is a pentacylic triterpene
derivatives of the β-amyrin type. Other constituents include flavonoid
glycosides, coumarin derivatives, glucoses, mannitol and 20% of
starch.

45.  Chemical Constituents:
 Uses:Uses:
 Glycyrriza possesses tonic, laxative, demulcent (a
substance which exerts a soothing or protective
influence upon the surface of the alimentary canal),
diuretic, emmenagogue (drugs which restore the flow
at the menstrual periods is scanty or absent) and
emollient properties.
 It is used as expectorant.
 Glycyrrhiza is used to cure rheumatoid arthritis,
Addison’s diseases and various inflammatory
conditions.

46.  Synonyms: Wild yam, colic root
 Botanical source: Dioscorea is the dried
roots and rhizomes of Dioscorea villosa,
belonging to the family Dioscoreaceae.
 Chemical constituents: Dioscorea is a source
of diosgenin. Diosgenin is obtained by
hydrolysis of dioscin which upon hydrolysis
yields diosgenin, rhamnose and glucose.

47.  Diosgenin, a steroid sapogenin, is the product of
hydrolysis by acids, strong bases, or enzymes of
saponins, extracted from the tubers of Dioscorea wild
yam. The sugar-free (aglycone), diosgenin is used for
the commercial synthesis of cortisone, pregnenolone,
progesterone, and other steroid products.
 Clinical uses
 Diosgenin is the precursor for the semisynthesis of
progesterone which in turn was used in early
combined oral contraceptive pills. The unmodified
steroid has estrogenic activity and can reduce the
level of serum cholesterol.
 Diosgenin may behave as a prodrug to progesterone.

48.  Cyanogenesis is the ability of certain living organisms,
plants in particular, to produce hydrocyanic acid (HCN,
prussic acid).
 Cyanogenesis in plants is a chemical defense mechanism
against organism damaging or feeding on plant tissues and
lead to release of HCN gas, which is toxic.
 They are distributed in over 2000 plant species belonging to
110 families.
 These compounds, in presence of enzymes such as β-
glucosidase, lose their sugar portion to form a cyanohydrin
which, in the presence of water and hydroxynitrile lyase,
can undergo hydrolysis to give benzaldehyde and the
highly toxic hydrogen cyanide (HCN).


49.  The sugar portion of the molecule may be a
monosaccharide or a disaccharide such as gentiobiose
or vicianose. If a disaccharide, enzymes present in
the plant may bring about hydrolysis in two stages, as
in the case of amygdalin.
 They are derivatives of α-hydroxynitrile or 2-
hydroxynitrile (cyanohydrins).
 In all cases the first sugar attached to the aglycone is
β-D-glucose.
 Most cyanogenetic glycosides are biosynthetically
derived from the amino acids: valine, leucine,
isoleucine, tyrosine or phenylalanine.

50.  Cyanogenetic glycosides are easy to detect with a strip
of filter paper impregnated with reagents able to give a
color reaction with the hydrocyanic acid released upon
crushing the plant material (e.g., picric acid/sodium
carbonate or benzidine/cupric acetate).
 Although hydrocyanic acid is a violent poison, it is
important to remember that oral intake of cyanogenetic
drugs does not necessarily cause severe intoxication,
this is because the range of dangerous concentrations
(0.5-3.5 mg/kg) can only be achieved by rapid and
massive ingestion of plant parts rich in cyanogenetic
glycosides.
 Examples:
 Amygdalin in bitter almonds (Prunus amygdalus). It is
biosynthetically derived from phenylalanine.

51.  Synonym: Wild cherry bark, Black cherries,
Prune bark.
 Botanical source: Wild cherry bark is the dried
bark of Prunus serotina from the family Rosaceae
which is habitat in United States and Canada.
 Characters:
 The drug occurs in curved or channeled pieces,
length up to 10 cm, width 5 cm, thickness 0.3-1.4 mm.
 Outer surface of unpeeled bark is reddish brown,
covered with thin papery, glossy, exfoliating cork cells.
 Outer surface without this cork cells is rough with
lenticles.
 Inner surface is reddish brown with striated reticulated furrows.
 The fracture is short.
 Slightly moist drug possesses benzaldehydic odour
 Taste is bitter and astringent.

52.  Chemical constituents:
 Wild cherry bark contains a cyanogenic glycoside, prunasin
(d-mandelonitrile glucoside). The enzyme prunase,
benzoic acid, trimethyl gallic acid, P-coumaric acid,
starch, tannin and volatile oil are the other chemicals.
 The enzyme prunase hydrolyzes prunasin to benzaldehyde,
glucose and hydrocyanic acid.
 Uses:
 Wild cherry is used for colds, whooping cough, bronchitis
and other lung problems; diarrhea; gout; digestive
disorders; pain; and cancer. It is also used in cough syrups
because of its sedative, expectorant, drying, and cough-
suppressing effects.
 In foods and beverages, wild cherry is used as a flavoring
agent.